Electric iron



Nov. 14,

TOSHIO YAl ET AL ELECTRIC IRON Fild Oct. 4, 1965' 3 Sheets-Sheet 1 ATTORNEYS Novym, 1967 T 'A. ETA-L I 3,352,998.

ELECTRIC IRON 3 SheetsSheet- 2 Filed on. 4, 1965 IN VEN TOR 5 ATTORNEYS W. a, R W NJ E n J b. M

TOSHIO YAI ET AL' 3,352,998

ELECTRIC IRON Nov. 14, 1967 Filed Oct. 4,1965

Power INVENTORS fish/'0 ya/ 61 Tkash iml ATTORNEYS United States Patent 3,352,998 ELECTRIC IRON Toshio Yai, Hirakata-shi, and Seiji Takashima, Amagasaki-shi, Japan, assignors to Matsushita Electric Industrial Co., Ltd., Osaka, Japan, a corporation of Japan Filed Oct. 4, 1965, Ser. No. 492,622 Claims priority, application Japan, Oct. 8, 1964, 39/80,114, 39/80,115, 39/80,116; Oct. 21, 1964, 39/83,147; Nov. 11, 1964, 39/88,317

Claims. (Cl. 219252) The present invention is to provide an improved and novel electric iron provided with adjusting means capable of adjusting the sole plate surface temperature to be most suitable for various kinds of cloth.

In recent days various kinds of chemical fiber cloth are being sold under the trade names, for example, of nylon and Tetoron, and for ironing out such cloth it is necessary to suitably select an ironing temperature for the respective cloth and adjust the sole plate surface temperature of iron to that temperature beforehand. In electric irons which have been available heretofore, however, the sole plate surface temperature is adjusted by temperature adjustment indicating means which is adapted to change the temperature from off position to a maximum temperature within one rotation of a manually operative thermo-adjustment dial and therefore a slight temperature adjustment to a selected temperature has to depend essentially on the feeling at a finger tip, with a consequence that an error with respect to a desired temperature is much greater.

A further detailed object of the present invention is to make the amount of temperature change according to an angle of rotation of a thermo-adjustment dial smaller so that a slight temperature change may be adjusted by normal manual feeling, that is to heighten the preciseness of adjustment, by the addition of a thermostat adapted to change temperature from off position to a maximum temperature upon rotation of the manually operative thermo-adjustment dial more than one circle and a mechanism relative to said thermo-adjustment dial.

Another object of the present invention is to provide an electric iron in which an improved and novel switching mechanism is provided in addition to the thermostat, said switching mechanism providing for smaller rotating operation of the thermo-adjustment dial for the temperature range from off position to a lower temperature of 80 C., which is practically not used and unnecessary, than that of ordinary thermo-adjustment dials. By the ordinary thermo-adjustment dials is meant such dials which are required to be rotated proportionally at a constant ratio of temperature change to rotational angle of the dial, even in the section corresponding to the temperature range (normally below about 80 C.) which is not used practically.

Further detailed objects, advantages, mechanism and method of operation of the present invention will be more apparent from an embodiment of the invention shown in the accompanying drawings, in which:

FIGURE 1 is a side elevational view showing a portion of an electric iron embodying the present invention in section;

FIGURE 2 is an enlarged perspective view of a unit consisting of the thermostat and the manually operative circuit switch shown in FIGURE 1;

FIGURES 3 and 4 are side elevational views illustrating the operation of the unit of FIGURE 2;

FIGURE 5 is an enlarged perspective view of a guide member and a thermo-adjustment shaft of the unit shown in FIGURE 2 in disassembled state;

FIGURE 6 is a perspective view of the forward portion of a lower grip of handle;

FIGURE 7 is an enlarged perspective view of a thermoadjustment dial;

FIGURE 8 is a back view of the thermo-adjustment dial;

FIGURE 9 is an enlarged perspective view of the forward portion of an upper grip and lower grip of the handle in disassembled state;

FIGURE 10 is a plan view of a decorative cover; and

FIGURE 11 is an electric circuit diagram of the electric iron of the present invention.

In FIGURE 1, reference numeral 1 is a sole plate and 2 is a mica-insulation type plate heater fitted in a recess formed in the sole plate in such a shape that said plate heater is snugly fitted therein. A plate heater pressing plate 3 is mounted on the plate heater 2 and is secured to the sole plate 1 by such means as screws, thereby holding the heater 2 in intimate contact with the sole plate 1. A thermostat 4 is mounted on the sole plate 1 by a screw 5 and is constructed in the manner described hereinafter. Namely, the thermostat comprises an upper contact arm 6 having a contact 6a at a point near the free end thereof, a lower contact arm 7 similarly having a contact 7a at a point near the free end thereof and a bimetal strip 8 having a bimetal insulator 9 rigidly fixed at its free end portion, said upper contact arm 6, lower contact arm 7, bimetal strip 8 and a terminal plate which will be described hereinafter, being disposed one on another with insulating washers 10 intervening therebetween and caulked integrally to a supporting member 12 by a rivet 11 penetrating through common holes perforated at the root each thereof. A thermo-adjustment shaft 13 is disposed vertically with the lower end screwed in a screw hole formed at the end portion of the supporting member 12, said thermo-adjustment shaft having formed at the central portion thereof a penetrating hole extending axially, with a screw slot formed therein, in which an adjustment screw 14 for the adjustment of temperature is screwed during assembling of iron. Inserted below and in contact with the lower end of said adjustment screw 14 is an insulating element 15 made of ceramics and having the lower end tapered, which is always kept in contact with the surface of said lower contact arm 7 through a hole bored in the upper contact arm 6. Upon rotating the thermoadjustment shaft 13, the adjustment screw 14 moves up and down along the lead of the screw, with the lower contact arm 7 in contact with the insulating element 15 moving vertically, whereby the space between the free end of the upper contact arm 6 and the bimetal insulator 9 is adjusted optionally for the adjustment of temperature, said bimetal insulator 9 being mounted to the bimetal strip 8 which warps upwardly upon heating.

As is shown in FIGURES 1 through 5, the upper end 16 of the thermo-adjustment shaft 13 has a thermo-adjustinent dial 17 (or a knob) fitted therein and is formed in the shape of a prism, such as, for example, a hexagonal prism. A slide ring 18 is fitted on the thermo-adjustment shaft 13 for vertical sliding along therewith and has one end of an L-shaped slide pin 19 welded to the side thereof. At the other end of the slide pin 19 extending downwardly, there is an insulating cap 20 securely fitted on the end extremity, said insulating cap being made of heat-resistant insulating materials, such as heat-resistant rubber. These slide ring 18, slide pin 19 and insulating cap 20 are provided separately from the contact of said thermostat for the purpose of rendering the rotational operation of the thermo-adjustment dial 17 small when temperature is changed from off position to C. (lower temperature or from 80 C. to the off position, that is the temperature range below 80 C. which is unnecessary from the standpoint of practical use. Numeral 21 indicates a spiral guide member which rotates together with the thermo-adjustment shaft 13 and forms a lead for the vertical movement of the slide ring 18 to depress a movable contact arm 27 to be explained later, the upper end of said guide member being inserted and welded in a hole formed in a ring cap 22, the shape of said hole conforming to the cross section at the upper end portion 16 of the thermo-adjustment shaft 13. As is shown in the drawings, said guide member 21 has an irregular pitch and this is for the purpose of achieving the object of present invention previously described. While the guide member 21 is shown in the form of a spiral wire in the embodiment, it is only an example and the same purpose may be attained by a spiral groove formed in the outer periphery of a cylinder. The com-v bination of said guide member 21 and ring cap 22 is fitted on the thermo-adjustment shaft 13 along with the slide ring 18 before the thermo-adjustrnent shaft 13 is screwed in the supporting member 12. Since, in this instance, the hole formed in the ring cap 22 conforms in shape to the cross section at the upper end portion 16 of the thermo-adjustment shaft 13, the ring cap snugly fits on the upper end portion 16. After the ring cap 22 is fitted on the upper portion 16, a stopper ring 23 is engaged with a groove 16a formed in the thermo-adjustment shaft 13 so that said ring cap 22 does not come off upwardly. Numerals 24 and 25 are terminal plates fixed intimately to the upper contact arm 6 and lower contact arm 7 respectively in electrically conductive contact therewith, while numeral 26 is a contact arm for fixing the manually operative circuit switch and numeral 27 a movable contact arm for said manually operative circuit switch. The fixing contact arm 26 has its one end fixed by means of welding to a projecting end of the terminal plate 24 of upper contact arm 6 and the other end provided with a fixed contact 26a. The movable contact arm 27 is formed of a spring material and one end thereof is fixed by welding to an outwardly projecting end of a terminal plate 46 which is caulked together with the upper contact arm 6, lower contact arm 7, bimetal strip 8 and the supporting member 12 as being insulated by the insulating washers, while the other free end is provided with a movable contact 27a. FIGURE 11 shows the electric circuit of the thermostat 4 and man'- ually operative switch.

A guide plate 28 extending upwardly from the side end of the supporting member 12 serves to prevent rotational movement of the vertically slidable slide pin 19 along with the rotation of the guide member 21 and simultaneously to define the range within which said slide pin 19 slides vertically. It is means for changing a rotational movement to a vertical movement and the lower end of said guide plate is welded to the supporting member 12, while at the upper portion there is formed an elongate hole 28a through which the axial portion of the slide pin 19 extends loosely for vertical movement.

A cover shell 29 is mounted on and fixed to the sole plate 1 by such suitable means as screws to cover the aforementioned thermostat and the upper opening of a lower grip 30 which is mounted on and fixed to the cover shell by such means as screws is covered by an upper grip 31, said lower grip and upper grip together forming a handle. In the upper opening of said lower grip 30, there is provided a hollow 32 for the accommodation of an adjustment indicating means, which will be de. scribed hereinafter, and a shoulder 33 is formed near the forward end portion of said hollow successively at such location as to ease the operation of the thermoadjustment dial 17 to be mounted at the upper end portion 16 of the thermo-adjustment shaft 13. At the center on the upper end portion 16 of the thermo-adjustrnent dial 17, there is provided a gear portion 35 having dents 34 arranged concentrically with the thermoadjustment dial 17 in equally spaced relation for the engagement with a bead chain 41 carrying a needle as will be explained later, while on the back side there, is provided a volute guide groove 36 (S 2 FlGUR ls a 8)- Numeral 37 indicates a stopper which defines the rota tional limit of the thermo-adjustment dial 1'7 and the lower end portion of which is loosely received in a sliding groove 38 formed in the upper surface of the shoulder 33 formed at the upper portion of lower grip 30, while the upper end portion thereof is loosely received in the volute guide groove 36 formed in the back side of said thermo-adjustment dial 17. As the thermo-ad justment dial 17 is rotated, the upper end of said stopper 37 in engagement with said guide groove 36 does not move in the rotational direction of said dial but moves only in the directions of arrows shown in FIGURE 6, so that the rotation of the thermo-adjustment dial 17 is stopped when the stopper 37 hits either one of groove ends 36a and 36b of said guide groove 36. A support stud 39 is provided within the hollow 32 at the rear portion of lower grip 30 in opposed relation to the gear portion 35 on the thermo-adjustment dial 17 for the engagement with the bead chain 41 of adjustment indicating means, said support stud 39 having formed therein an engagement groove 40 for preventing disengagement of said bead chain 41 therefrom. The bead chain 41 constitutes the adjustment indicating means and has both ends connected by a spring 41a to form an annular shape and mounted over the gear portion 35 of the thermoadjustment dial 17 and the engagement groove 40 of the support stud 39 in an oval shape under tensed condition. This bead chain 41 is arranged such that, as the thermo-adjustment dial 17 is rotated, a section of beads is carried in the rotational direction of the dial by the dents 34, with the other section of the beads sliding also in the rotational direction in engagement with the engagement groove 40. Numeral 42 is a U-shaped scale plate provided above the forward portion of the thermo adjustment dial 17 and the bead chain 41 mounted thereon in such manner as to cover the same and is secured by a leaf spring 43 together with the thermo-adjustment dial 17, said leaf spring being fixed by a screw to a shoul der 30a of the lower grip 30 adjacent to the rear end portion of said scale plate for depressing the thermo adjustment dial 17. A U-shaped slot is formed in the interior of said scale plate 42 such that when said plate is mounted, the edge 42a of the slot is aligned to the configuration of the forward portion of the bead chain 41 as being mounted in the manner previously described. The needle 44 has one end welded to a specific one of a number of beads forming the bead chain 41, with the other end extending upwardly beyond the 'U-shaped slot 42a in the scale plate 42 with the tip flexed over said scale plate to indicate a scale 42b. The scale plate 42 is covered by a transparent U-shaped decorative cover 45 which is fitted in a protruding edge formed at the forward portion of upper grip 31 and has formed therein a U-shaped slot 45a conforming to the U-shaped slot 42a of the scale plate 42.

'When the needle 44 indicates the off position on the scale plate 42, the upper end of the stopper 37 is located at the inner groove end 36a of the guide groove 36 in the thermo-adjustment dial 17. Upon rotating the thermo-adjustment dial 45 degrees from this position, the needle 44 indicates the number of the scale 42b on the scale plate 42, and further rotation of the dial by 45 degrees brings the needle 44 to indicate the number 90. As such, a temperature change of 10 C. may be obtained by every rotation of the dial by 45 degrees. When the needle indicates 200 which is the scale for the maximum temperature, the upper end of stopper 37 comes in contact with the outer groove end 366 of the guide groove 36 in the thermo-adjustment dial 17 with the lower end moving within the slide groove 38 in the direction of F, whereby the rotation of thermo-adjustment dial 17 is stopped. It should also be noted that click stoppers may be provided for every 45 degree rotation (corresponding to a temperature change of 10 Ci), of the thermo-adjustment dial 17, said clock stopper consisting of a click stopper 47 and a spring 48 shown in FIGURE 1 and engaging in abutting relation with radial click stop grooves 49 formed on the back side of the thermo-adjustment dial 17 as shown in FIGURE 8.

What is claimed is:

1. An electric iron comprising a sole plate to be heated by a plate heater, a thermostat thermally conductively mounted on said sole plate, a cover shell for covering said thermostat and mounted to the sole plate and a handle mounted to said cover shell, said thermostat consisting of upper and lower contact arms each having a contact provided in opposed relation to another for engagement and disengagement, a bimetal strip provided at its free end with a birnetal insulator provided in opposed relation to the free end of said upper contact arm, a supporting member to which said upper and lower contact arms and said bimetal strip are integrally secured by caulking at their root portions in juxtaposed relation with insulating layers intervening therebetween and a thermoadjustment shaft for adjusting the space between the free end of said upper contact arm and said bimetallic insulator, said thermostat being provided with a slide ring fitted on said thermo-adjustment shaft and having a slide pin mounted to the side thereof, a guide member formed into a spiral lead which is adapted to rotate integrally with said thermo-adjustment shaft more than one circle to cause a vertical movement of the slide ring, a manually operative circuit switch consisting of a fixed contact arm extending from a terminal plate electrically conductively connected to said upper contact arm and having a fixed contact and a movable contact arm assembled integrally with said thermostat, while being electrically insulated therefrom, having a movable contact thereon and made of a flexible material, and a guide plate disposed between said thermo-adjustment shaft and said manually operative circuit switch and adapted to change the movement of said slide pin caused by the rotation of said guide memher into a vertical movement so as to have said pin slide 'vertically within a controlled range, said slide pin opening said manually operative circuit switch when it reaches the lowermost position.

2. An electric iron according to claim 1, which is provided with a thermo-adjustment dial mounted integrally to the upper end of thermo-adjustment shaft of said thermostat and having on the back side thereof a volute guide groove, and a retractable stopper elastically and loosely received in a slide groove formed in a handle portion opposite to the back side of said thermo-adjustment dial in such a manner that its top end always projects above the slide groove, and adapted to control the rotational range of the therrno-adjustment dial by engagement with said volute guide groove.

3. An electric iron according to claim 1, which is provided with adjustment indicating means comprising a gear portion disposed at the center on the upper surface of a thermo-adjustment dial mounted integrally to the upper 6 end of thermo-adjustment shaft of said thermostat and having on its peripheral side dents arranged concentrically with said thermo-adjustment dial in equally spaced relation, a supporting stud projecting within a hollow at the rear portion of a handle in opposed relation to said gear portion and having an engagement groove, a bead chain mounted over the dents in said gear portion and the engagement groove in said support element under tension, a U-shaped scale plate provided above the forward portion of said thermo-adj-ustment dial and the bead chain mounted thereon so as to cover the same and a needle fixed to said bead chain and adapted to move along the edge of a U-shaped slot formed in the interior of said scale plate together with said bead chain to thereby indicate a scale.

4. An electric iron according to claim 3, which is provided with a transparent decorative cover mounted to the forward portion of the handle to cover said scale plate and having formed therein a U-shaped slot conforming to the U-shaped slot of said scale plate.

5. An electric iron according to claim 1, which is provided with a thermo-adjustment dial mounted integrally to the upper end of thermo-adjustment shaft of said thermostat and having on the back side thereof a volute guide groove, a retractable stopper elastically and loosely received in a slide groove formed in a handle portion opposite to the back side of said thermo-a'djustment dial in such a manner that its top end always projects above the slide groove and adapted to control the rotational range of the thermo-adjustment dial by engagement with said volute guide groove, and adjustment indicating means comprising a gear portion disposed at the center on the upper surface of the thermo-adjustment dial mounted integrally to the upper end of thermo-adjustment shaft of said thermostat and having on its peripheral side dents arranged concentrically with said thermo-adjustment dial in equally spaced relation, a supporting element projecting within a hollow at the rear portion of the handle in opposed relation to said gear and having an engagement groove, a bead chain mounted over the dents in said gear portion and the engagement groove in said support element under tension, a U-shaped scale plate provided above the forward portion of said thermo-adjustment dial and the bead chain mounted thereon so as to cover the same and a needle fixed to said bead chain and adapted to move along the edge of a U-shaped slot formed in the interior of said scale plate together with said bead chain to thereby indicate a scale.

References Cited UNITED STATES PATENTS 2/1954 Vance 6/1962 Knapp 

1. AN ELECTRIC IRON COMPRISING A SOLE PLATE TO BE HEATED BY A PLATE HEATER, A THERMOSTAT THERMALLY CONDUCTIVELY MOUNTED ON SAID SOLE PLATE, A COVER SHELL FOR COVERING SAID THERMOSTAT AND MOUNTED TO THE SOLE PLATE AND A HANDLE MOUNTED TO SAID COVER SHELL, SAID THERMOSTAT CONSISTING OF UPPER AND LOWER CONTACT ARMS EACH HAVING A CONTACT PROVIDED IN OPPOSED RELATION TO ANOTHER FOR ENGAGEMENT AND DISENGAGEMENT, A BIMETAL STRIP PROVIDED AT ITS FREE END WITH A BIMETAL INSULATOR PROVIDED IN OPPOSED RELATION TO THE FREE END OF SAID UPPER CONTACT ARM, A SUPPORTING MEMBER TO WHICH SAID UPPER AND LOWER CONTACT ARMS AND SAID BIMETAL STRIP ARE INTEGRALLY SECURED BY CAULKING AT THEIR ROOT PORTIONS IN JUXTAPOSED RELATION WITH INSULATING LAYERS INTERVENING THEREBETWEEN AND A THERMOADJUSTMENT SHAFT FOR ADJUSTING THE SPACE BETWEEN THE FREE END OF SAID UPPER CONTACT ARM AND SAID BIMETALLIC INSULATOR, SAID THERMOSTAT BEING PROVIDED WITH A SLIDE RING FITTED ON SAID THERMO-ADJUSTMENT SHAFT AND HAVING A SLIDE PIN MOUNTED TO THE SIDE THEREOF, A GUIDE MEMBER FORMED INTO A SPIRAL LEAD WHICH IS ADAPTED TO ROTATE INTEGRALLY WITH SAID THERMO-ADJUSTMENT SHAFT MORE THAN ONE CIRCLE TO CAUSE A VERTICAL MOVEMENT OF THE SLIDE RING, A MANUALLY OPERATIVE CIRCUIT SWITCH CONSISTING OF A FIXED CONTACT ARM EXTENDING FROM A TERMINAL PLATE ELECTRICALLY CONDUCTIVELY CONNECTED TO SAID UPPER CONTACT ARM AND HAVING A FIXED CONTACT AND A MOVABLE CONTACT ARM ASSEMBLED INTEGRALLY WITH SAID THERMOSTAT, WHILE BEING ELECTRICALLY INSULATED THEREFROM, HAVING A MOVABLE CONTACT THEREON AND MADE OF A FLEXIBLE MATERIAL, AND A GUIDE PLATE DISPOSED BETWEEN SAID THERMO-ADJUSTMENT SHAFT AND SAID MANUALLY OPERATIVE CIRCUIT SWITCH AND ADAPTED TO CHANGE THE MOVEMENT OF SAID SLIDE PIN CAUSED BY THE ROTATION OF SAID GUIDE MEMBER INTO A VERTICAL MOVEMENT SO AS TO HAVE SAID PIN SLIDE VERTICALLY WITHIN A CONTROLLED RANGE, SAID SLIDE PIN OPENING SAID MANUALLY OPERATIVE CIRCUIT SWITCH WHEN IT REACHES THE LOWERMOST POSITION. 